Incandescent light bulbs are gradually being replaced by light-emitting diodes (LEDs) in many applications. LEDs have many advantages over traditional incandescent lamps in that they have longer operational life, reduced power consumption, greater durability and increased design flexibility.
Despite these advantages, at present LEDs are not used in all applications. LEDs commonly operate on a supply of DC. Accordingly, many applications that use LEDs require conversion of an AC power supply to a DC power supply. For example, U.S. Pat. No. 7,049,761 assigned to the assignee of this invention, discloses a power supply circuit that includes a rectifier circuit and a PWM switching circuit. The rectifier converts AC power to DC power and the PWM switching circuit receives the DC power and pulse-width modulates the DC power to supply an LED array. Known converters are not practical for use with some LED applications because of their size and excessive cost. Passive components such as capacitors and inductors within known converters become larger as operating voltages increase thereby increasing the overall size and cost of the LED device.